Tire-casing.



J. P. PALMER.

TIRE CASING.

APPLIUATION FILED JAN. 2,

Patented" June 8, 1909.

v he. 924,268.

45 of the immediate ccntei theme 50 curve Whichcoucects two parts t 1s sharpened 1m sharpen ng thzs'flco'hwc,

JOHN F, PALMER, OF Cl-lIl'JAGG, ELL IITOIS.

Tum-chemo Application filed January 2, 1905.; Serial No. 29%,113.

'fl'h'dll'whom it may concern Be 1t known that 1, JOHN F. lALmm, .21 *i'ilillZGIi of the United States of America,

siding Chicago, in the county of Cook 5 hliitlfSt cte of Illinois, have ihwmted certain new and useful Improvements in TH8GBS- 5,01 which the following IS a specifics My im'er tion relates to improvements in 10 tire casings and is fully described and era-- plowed in this specification and shown in. the"accompanying drawings, in Wluch- Figure 1 is El, tiansyerse section through nnpro ed tire and the mandrel upon which the some is formed; Fig. 2 is transverse on through the same tire when ihfla-tcd; and l 'ig. 8 a siiiniloi' section through the are when inflated and supportlllg zpfwciglnz, the section being through the 0 portiozi oi the twain contact With the ground and flattened by such contact, r

In pneumatic tires, particularly the tires on the driving wheels of a motor Vehicle,

there has heretofore been a large amount of weal-for the following reason: JVhen tire is blown up to a high pressure, it tenols to take a form where the inner surface the treecl is curved in the arc of a cccle in cross seztioc, and most tires have heel 11 built on ie-m Eels such form that the portions of the tires have a 'c'uiwel ihner 'sii tface-of this form when on .themendreh Furtl more, most tires have incorporated in the body 2; plurality of layers of fabric of some kinclend these/layers are normally of substantially equal tension when ltlfi. upon the mandrel and also when the tire is' inflated. l/Vhen, in sdliitioh 111* fizitedfiwieight is placed upon "-he'ci' livery; 40 two, thctx'ccd flattens to cgzcetiteit less extentdopcncnt upon the amount o. interns pressure :mol theamcunt of? Wei .eppliekl, and, he a result, curvctw thosepoi tiohs of thc tir e w s the cuii've'tuie hecomh'lg shsi'pec. in otl I words, if the expression may he used, the angle between the title walls 025 the tire anti the thread is .eiecrezi-sedchd the Specification of Letters ijstent. 1 i

, or 1 we to expand at all, but act to a certain extent Patented Jul 1g: c, 1909.

either tihc inner portions of the tire Wall must shorten or the outer portions of fithe the wall must lengthen. Inasmuch as the feline of which the tire is composed 1s usuclly comparatively 'nonclastic, but is more flexible, the outer laye s are unable as c. A about which the fiectio'n of the tire. Wall takes place, and the inner fabric layers are shoi tencol up, c 'lnkled, loosened, and vcryiorcihly crowded together; Tlus crowd-mg; and compressing of the inner layers occurs, it 111 hciohserved, in each portion of the the just when thatportion is" in 'contcct'with; the ground and is operating to transmiUpoi-ver; 2'. e. at the time when the tensionon the fabric of the tire is at its maxim-mm As a result of the simultaneous ccu-rre -e"-ot the fabric compression and fabric strain, 21' large amount of wear is caused which would not take place were all threodskept taut at this time. i The 'ordlnai'y pneumatic, the 111 common use, vrcsvs out (1n :1 very large number of cases) along the lines where the bend from the side walls to the tread occurs when the,

tire suhje'ctefl to pressure and weight, and

th wen-r on the tire occurs firston the in; sltlc layers. It frequently hop 36118, for m:

stance, that the inner layers 0 1 tire" give,

out alon this line While the outer laf'ers re con'lpomtively intact. "lhis Weak point in the tire has liicci'i long recognized, but the causes of its Weakness have never been appreciatai; Various remedies have been at temptel mostof ,WhlCh consist 111 adding strong,

tioio (ifhe causes of eakness that every a; layer I .i Wall causes a glfcster compression ofthe inner ,.hehi ng fabric to this'weak line. "will he obvious from the foregomgdescnp placed upon this vportioncf the yer-s end. i icrccses rather; than, decrease the -d1i'liculty. .The two lllustratc'd i to aVOlt'lYu'fiEll" on this weake cd' li ein the j following manner-:1 build the tire over av.

mandrel; which I pnefez' to make with at.

iiet treml and compcjmtivelyfist,side' walls 21mlwlth curved; portlons, a, conncctmgthe tread snclf srle walls. Itwfll he seon'that the c'i'ossseclionelcurvatui'e of'these curi'red in dottedlin'es in portions, a, is comparatively sharp, the circle Fig. 1 showing the radius of the curve. I prefer also to build up the tread of the tire to a considerable thickness as illustrated.

In the accompanying drawings, reference character; B iiidicates the tire casing which is provided witha thickened tread b, and

- with longitudinal ribs 6 and b around its in inner edges, the latter for the purpose of interlocking with the intui'ned flanges e and e of the rim E. O indicates the strain resisting fabric in the casing B, while D indicates the usual inner tube of a double pneumatic tire.

When the tire is inflated it takes the position shown in Fig. 2 where it is approxiconnecting the tread .tenedout to a certain extent, the tendency being to place the said walls under mately circular words,

in cross-section." In other the curved portions of the tire walls and side walls are flatouter layers of fabric in a slight compression.

Those portionsof the tire which are, howv the tread is flattened out and the fabric in thewalls takes the form illustrated. It will be seen that in the,construction here illustrated, the inner surface of the tread is curved inward slightly but that the curvature of that portion of .the tire on the two sides of the flattened portion is exactly or almost exactly that which it had when it was first built on the mandrel. In' this way it is possible to construct a tire which when subjected to both pressure andthe weight of the vehicle has all its fabric layers under substantially similar conditions. If, .for instance, it be assumed that all the layers be put on the mandrel with equal tension, they will be equally tight when subjected to pressure and weight.

To sum the matter up, I reverse the ordinary pneumatic tire practice. -Heretofore it has been customary to build a tireover a mandrel of such form that when the tire is 111- lace on the mandrel it occupies substantia y the cross-sectional form which it occupies when subjected to internal pressure but not-to weight, whereby the tire when sub-.

jected to. both weight and pressure takes an abnormal curve on the two sides of the tread ortion, with the resultsalready set forth. nthe contrary, I :build 'my tire in such form'that the portionsf'whichare necessarily subjected to the greatest range of curvature occupy their abnormal position when sub- .jected to pressure alone,

-That portion of the .th-ickened portion of the and return toward z. a. the position in when sub ected both their normal position, which they were built to pressure and weight.

As already pointed out, the rubber coating of the tire casing is thickened on the tread. This construction is highly desirable because when the tire is subjected to pressure and weight, the side walls tend to bulge out at the point where the pressure is applied. The thickening of the tread causes the center of the tread to pushin at the same time,'so that the angle between the two sides of the line separating the tread and the side walls is maintained in its proper relation.

From the foregoing description of my tire, it will be seen that my invention is not at all dependent upon the details of construction involved, nor upon its being constructed in a particular manner or of particular materials. In fact, my invention can be embodied in tires of almost every conceivable shape, form, and substance, the articular form herein shown and described sing the one in which I have embodied myinvention,

and in which I find it works satisfactorily.

I claim as new and desire to secure by Letters Patent l A pneumatic tire providedwith strain resisting fabric therein and in which the curvature of the portions of the wall at each side of the tread issubstanti'ally the same both when the tire is inflated and supporting a load and when deflated and not supportinga load.

2. A pneumatic tire provided with a alu rality of layers of strain resisting fa ric therein and in which the curvature of the portions of the wall at each side of the tread 18 substantially the same both when the tire is inflated'and supporting a load and when deflated and not supportin a load.

3. A pneumatic tire provided with strain. resisting fabric therein and having a tread thicker at the longitudinal center than at the longitudinal sides thereof, and also-having a substantially flat internal surface alinin r with the thickened portion of the tread: whereby when the tire is inflated and su ports a load the thickened portion of tie tread imparts a reverse curve to the fabric on the tread, thereby givin a curvature to;

the portions of the tire wal at each side of the tread substantially the same as when {he tire is deflated and not supporting a oad.

4. A pneumatic tire provided with a lurality of layers of strain-resisting fa ric therein and having a tread thicker at the longitudinal center than at the longitudinal sides thereof, and also having a substantially flat internal surface alinin with the thickened portion of the tree. whereby when the tire is inflated and supports a load the tread imparts a reverse curve to the fabric on, the trflad, cago, in the county of Cook and State of thereby giving a curvature to the portions Illmois, this 17th day of December A. D. r of the tu'e wall at each side of the tread 1909.

t siibstantiall the same as when the tire is JOHN F. PALMER. -5 deflated an not'supportin a load. Witnesses:

.In witness whereof I ave signed the- CHAS. O. SHERVEY, above applic'ation for Letters Patent at Chi- I K. M. CORNWALL. 

